As a common harvester combine machine moves forward through a crop such as wheat, the wheat is cut and conveyed upwardly into the combine, and into a threshing cylinder mounted therein where the grain is stripped from the wheat stalks. The grain is then conveyed by the combine to a series of sieves where the chaff is blown away from the grain by blasts of air. The grain separated from the chaff is then conveyed within the combine to a grain chute, while the straw stalks and chaff are typically conveyed or blown rearwardly to fall upon the ground through a rear straw and chaff output port. In the absence of some mechanism for broadcast spreading the straw and chaff, the straw and chaff typically falls into elongated piles trailing behind the combine harvester.
Such piles of straw and chaff tend to soak up herbicide subsequently spread over the ground, preventing weed seeds underlying the piles from being killed. Thus, after a wheat harvest where such piling of straw and chaff is allowed, rows of undesirable weeds may grow. Where the straw and chaff is evenly spread over the ground, subsequent application of herbicide will effectively and consistently treat the ground and kill all weed seeds.
A known, but deficient, method of spreading straw and chaff emitting from the rear output port of a harvester combine is to rotatably mount a pair of circular spreader plates side by side beneath the combine's rear straw and chaff output port. Such spreader plates typically have spreader fins extending upwardly from their upper surfaces. Viewing such spreader plates from above, the plates are rotatably driven by gear driven axles so that the left spreader plate rotates in a clockwise direction, and so that the right spreader plate counter-rotates counter-clockwise. Such counter-rotation of the left and right spreader plates causes the spreader fins to propel straw and chaff rearwardly away from the harvester combine. A presumed advantage of such counter-rotation of the left and right spreader plates and fins is that straw and chaff falling from the output port upon the discs is not thrown by the fins forwardly toward the combine and toward the output port. A disadvantage of such counter-rotation of the left and right spreader plates and fins is that the straw and chaff is thrown rearwardly in a relatively concentrated stream, resulting in undesirable accumulation of the straw and chaff behind the harvester combine.
The instant inventive straw and chaff spreading assembly eliminates such undesirable rearward concentration of straw and chaff by reversing the counter-rotation of the spreader plates and by interposing an arcuately curved deflector shield between the spreader plates and the harvester combine; the shield accommodating for straw and chaff thrown forwardly by the spreader plates. The combined actions of the reverse counter-rotating spreader plates and the deflector shield results in true broadcast spreading of straw and chaff which emits from the straw and chaff output port of the harvester combine.